The .577/450 was based upon the same separate steel head used for the .577 Snidercartridge, with a wrapped foil body firing a nominally .45 calibrebullet, giving the cartridge a "bottle-necked" appearance. Initially, .577/450 cartridges were manufactured of rolled brass foil, but later on- shortly after the Anglo-Zulu War- it was discovered that the rolled foil cartridges were prone to jamming as the barrel heated up, and production was switched to the drawn brass style now commonly used for the manufacture of small arms ammunition.

The Martini-Henry single-shot lever action rifle had a Martini designed action married with the unique rifling designed by Alexander Henry. The first three patterns or "Marks" were equipped with a shorter lever, which was extended in the Mark IV pattern to address extraction problems in some climates. The Mark IV was the final and most refined form of the rifle in 577/450, but was already obsolete owing to the pending adoption of a smokeless powder small bore cartridge, which became the .303.